Many and various rotatable seal assemblies have been suggested for sealing the space between a rotating shaft and a stationary housing. Many such seal assemblies involve positioning of sealing rings about a shaft to provide a seal assembly to prevent fluid flow between the shaft and the fixed housing. One example of such a complicated structure is depicted in U.S. Pat. No. 4,625,977 to H. Azibert et al. However, such seal assemblies are complex and very expensive to manufacture and result in significant down time to the machinery operation when such seal assemblies become clogged or inoperative. Additionally, when such seal assemblies are positioned between the rotating shaft and the fixed housing, problems of alignment oftentimes occur between the various sealing faces of the seal assembly.
Other types of rotatable seal assemblies permit the introduction of grease or lubricant within the sealing structure to flush the sealing structure and prevent contaminants from entering the seal between the rotating shaft and fixed housing. Again such seal structures are complicated and oftentimes include sealing washers and rollers which are extremely expensive and do not provide alignability between the rotating member and the fixed housing. One example of such a prior art structures is shown in U.S. Pat. No. 4,411,437 to R. Conti.
Still other types of rotatable seal assemblies are mounted within the fixed housing and include an annular sealing member which engages and seals against the rotating shaft. However, such sealing structures permit the introduction of contaminants to penetrate between the sealing face and the rotating shaft thereby resulting in increased wear to the shaft and the attendant loss of the seal between the rotating shaft and the fixed housing. An example of such a sealing assembly is shown in U.S. Pat. No. 2,960,355 to J. Bayerl.